基于查表原理的单对磁极编码器研制

与光电编码器相比,磁性编码器结构简单、易微型化、且不受尘埃及结雾的影响,但其分辨率和精度较低且难以提高,严重制约了其应用和发展。针对单对磁极编码器,深入分析了传统处理方式上存在的缺陷,提出一种基于标定查表的信号处理方式。采用六路霍尔传感器均布在圆周上,把变化的磁场转换成电压信号,经差分得到查表用三相电压信号。在离线状态下,用高精度光电编码器对电压信号与电机旋转角度进行标定,并把角度数据存储在EEPROM中。工作过程中采用三相电压信号分区间查表得到电机旋转角度值,用FPGA(programmablegatearrayField)进行信号处理,实现了分辨率15位,精度14位(16384线)的角度输出,能够满足电机恶劣环境下高精度位置检测的要求。

Design of Single Pair-pole Magnetic Encoder Based on Looking-up Table

Compared with an optical encoder,the structure of a magnetic rotary encoder is very simple and not affected in dust and mist condition.But its resolution and accuracy are low and difficult to be improved,so the application was limited.The disadvantage of conventional processing method was discussed deeply and a novel signal-processing method based on looking-up table was proposed to improve accuracy of the single pair-pole encoder.The magnetic filed,which was changed when the motor was rotating,was sensed through six Halls placed along a circle evenly,three voltage-signals were get through difference.A higher resolution optical encoder was used to calibrate the magnetic encoder and the data of the angle was stored in EEPROM off-line.While the encoder was in working state,the angle was got through looking-up table according to different voltage-signal in different region,all of the processing was done by FPFA.A single pair-pole magnetic rotary encoder was made according to this method and its characters were tested.The result shows that its accuracy is 14-bits(16384 lines)and resolution can achieve to 15-bits.It can be used in a badly conditon where a high-accuracy position-detecting must be realized.